Oldfart wrote:I'm looking for a low-cost totalizer to measure CO2 flow. It's a thingy like the gas meter that you may have in your house, it measures gallons or cubic feet of gas used over time. Any ideas?

Try http://www.vernier.com , which sells a CO2 sensor for $250. In addition to that you will need a LabPro interface, which costs another $220

The great thing about the Vernier system is that it can work on its own or plugged into the computer to collect data. It can also accept other probes that could make for an intereting experimental session. For example, you could simultaneously measure the CO2 evolution, dissolved oxygen concentration, temperature, and pH of the brew.